[pulse] check formula unsat more often
[pulse] check formula unsat more often

Summary:
Now that this is a cheap operation, use it whenever we are checking the
satisfiability of the path condition.

Reviewed By: skcho

Differential Revision: D22724373

fbshipit-source-id: df31c6010

facebook/infer,facebook/infer,facebook/infer,facebook/infer,facebook/infer,jvillard/infer,facebook/infer,jvillard/infer,jvillard/infer,facebook/infer,jvillard/infer,jvillard/infer,jvillard/infer,jvillard/infer